java 解决文件名重复问题的两种方法

   public static File createOrRenameFile(File from){
        String[] fileInfo = getFileInfo(from);
        String toPrefix=fileInfo[0];
        String toSuffix=fileInfo[1];
        File file;
        file = FileUtils.createOrRenameFile(from, toPrefix, toSuffix);
        return file;

    }

    /**
     * sdcard/pic/tanyang.jpg
     *
     * toPrefix: tanyang
     * toSuffix: tanyang.jpg
     * @param from
     * @param toPrefix
     * @param toSuffix
     * @return
     */

    public static File createOrRenameFile(File from, String toPrefix, String toSuffix) {
        File directory = from.getParentFile();
        if (!directory.exists()) {
            if (directory.mkdir()) {
                Log.v(TAG, "Created directory " + directory.getAbsolutePath());
            }
        }
        File newFile = new File(directory, toPrefix + toSuffix);
        for (int i = 1; newFile.exists() && i < Integer.MAX_VALUE; i++) {
            newFile = new File(directory, toPrefix + '(' + i + ')' + toSuffix);
        }
        if (!from.renameTo(newFile)) {
            Log.w(TAG, "Couldn't rename file to " + newFile.getAbsolutePath());
            return from;
        }
        return newFile;
    }

/**
     *
     * @param from
     * fileInfo[0]: toPrefix;
     * fileInfo[1]:toSuffix;
     * @return
     */
    public static String[] getFileInfo(File from){
        String fileName=from.getName();
        int index = fileName.lastIndexOf(".");
        String toPrefix="";
        String toSuffix="";
        if(index==-1){
            toPrefix=fileName;
        }else{
            toPrefix=fileName.substring(0,index);
            toSuffix=fileName.substring(index,fileName.length());
        }
        return new String[]{toPrefix,toSuffix};
    }

public static String generateSuffix() {
        // 获得当前时间
        DateFormat format = new SimpleDateFormat("yyyyMMddHHmmss");
        // 转换为字符串
        String formatDate = format.format(new Date());
        // 随机生成文件编号
        int random = new Random().nextInt(10000);
        return new StringBuffer().append(formatDate).append(
                random).toString();
    }

    public static File createFileWithCurDate(File from){
        String[] fileInfo = getFileInfo(from);
        String toPrefix=fileInfo[0]+generateSuffix();
        String toSuffix=fileInfo[1];
        return new File(from.getParent(),toPrefix+toSuffix);
    }